Pile chucks for vibratory drivers



April 14, 1970v T. N. GAFENCU PILE CHUCK S FOR VIBRA'I'ORY DRIVERS l Filed May 24, 1967 TR A l AN N ECULAE GAFENCU IN VEN TOR. o

ATTORNEY United States Patent 3,506,278 PlLE CHUCKS FOR VIBRATORY DRIVERS Traian Neculae Gafencu, Bucharest, Rumania, assignor to Ministerul Transporturilor Auto Navale, Si Aeriene, Bucharest, Rumania, a ministry of Rumania Filed May 24, 1967, Ser. No. 640,943 Claims priority, application Rumania, June 22, 1966,

Int. Cl. i211) 1/10 U.S. Cl. 2794 3 Claims ABSTRACT OF THE DISCLOSURE A chuck for a vibratory driver or puller having a downwardly open chamber of prismatic configuration and a clamping element movable on a window in a wall of the chuck for engagement with a pile received therein. The clamping plate is provided with a spring plate lying parallel to this wall and biasing the clamping member into the window against the pressure of a diaphragm of a hydraulic chamber in this wall which is pressurized to drive the clamping member against the pile and hold it against an opposing wall.

The invention relates to chucks for establishing a connection between unidirectional vibrators and piles or tools upon which the vibration forces are to be exerted.

Such chuck is used especially for pile driving or withdrawing sheet-pilings and tubing for the compressing of soils, for dynamic testing of subsurface structures (socalled test piles), for the drawing of plates and for other operations, which can be carried out by vibration techniques.

There are known connection chucks for vibrators which effectuate rigid joining by using conical wedges, or inclined-range wedges, or screw-type attachment flanges and hydraulic tongs.

The devices with wedges and flanges have the disadvantage that they require considerable manual work for the establishing the connection and the detachment thereof; the respective operations have in many cases to be carried out in dangerous positions and they prolong the duration of the operations.

Conventional hydraulic chucks achieve rigid attachment between vibrator and object by introducing the end of the object into an open chamber, where the object is pressed against one or two lateral walls by clamping elements, pressed by the pistons of hydraulic cylinders, have the disadvantage that the parasitic vibrations between the clamping elements and the link and between the hydraulic cylinders and their pistons are not suppressed; these parasitic vibrations lower the efficiency of the force transmission and cause rapid wear of the device.

The known fixing chucks have also the disadvantage that the vibrating engine must be supplemented by engines or mechanisms for raising the object, thereby complicating the working unit and the working process.

Furthermore, hitherto known chucks cannot be voluntary untied or re-established during use for subjecting the object either to vibrations or to periodical shocks, as re= quired; this is a substantial drawback, considering that periodical shocks may frequently be very advantageous for the penetration in mediums with a high limit of elasticity.

:It is the object of this invention to provide an improved chuck of the character described which obviates the aforementioned disadvantages.

According to the invention, a chuck comprises a metallic frame, open at its lower part, in which the top end of the pile of the implement to be subjected to the action 3,506,278 Patented Apr. 14, 1970 of vibrations may be pressed against one or two walls by one or two pressing plates attached to one or two op posed walls, by spring-plates, parallel to the axis of the frame and the axis of the vibrating force (in their free or disengaged position); these pressing plates are hidden in their disengaged position in the surface of the frame walls, while in their clamping position they emerge from the plane of the walls and press upon the implement, the pressing plates themselves being pressed by very strong forces exerted by the diaphragms of hydraulic chambers. These diaphragms, of an adequate profile, are actuated by hydraulic pressure.

An embodiment of the invention is described below, reference being made to the accompanying drawing, the sole figure of which is an elevational perspective view, partly cut away, of a chuck according to the invention.

Referring to the drawing, a connection chuck consists of a metallic frame 1 having a cavity which is open at the lower end of the frame. The top of the pile or the implement 9 is pressed upon one or two lateral walls of the cavity, by one or two pressing plates 2 which pass through the opposed lateral walls. The plates 2 are carried by spring plates 3 parallel to the common axis of the frame and of the exciting force. Before engagement with the pile 9, the plates are hidden in or withdrawn into the windows 6 of these walls by springs 3, while in their fixing position they pass through the plane of the walls and press on the flanks of the object, the plates being pressed by the profiled diaphragms 4 of a hydraulic chamber.

In order to restrict the effect of wear and also for the amplification of the frictional forces the walls of the chamber and the pressing plates are lined with wearplates, as antifrictional plates 6 of a simple and easily replaceable construction.

The chamber 5 of the chuck and the clamping elements is balanced by an adequate counterweight 7, in order that the center of gravity of the apparatus lies in the direction of the exciting force.

For chucks which have to be equipped to release the object, the chamber has such a depth as to ensure that the clamping elements will be retracted from the cavity after the cessation of the hydraulic pressure and the vibrator together with the chuck, rests on the top of the object.

On the border of at least two diametrically opposed walls of the chamber are attached two cables 8, permitting the crane to hoist, together with the vibrator, the pile or the implement which has to be subjected to the vibration, or other objects of tools which may be used in the work ing process; the ends of these cables are connected to the corresponding ears of the object 9; after having been utilized as elements for hoisting the object, the cables remain as safety links between objects and vibrator.

The figure shows a chuck for piles, sheet-pilings, tubings or rams, with square, circular or polygonal sectioned bodies or at least tops; in this example, a fixed pile of square section is shown.

In a similar way, the chuck may be for sheet-pilings, piles or tubings, right or spiral of rectangular or lenticular section, devices provided with only one clamping plate or with two clamping plates.

The operation for driving in piles or sheet-pilings with a vibrator equipped with a chuck according to the invention, proceeds as follows:

In phase I, the crane on which the vibrator (not shown), provided with a chuck according to the invention, is suspended (by a device for an elastic suspension, if this equipment-unit is utilized for pulling), brings the vibrator and chuck near the pile and thus permits the cables or chains 8 of the device to be bound to the ears of the pile 9 which is to be hoisted and/or driven.

In phase II the crane hoists the vibrator chuck and thus also the pile, which passes from the horizontal in a vertical position.

In phase III the crane moves the pile to the place where it has to be driven into the ground.

In phase IV the pile together with the vibrator are lowered till the pile is lightly planted by its own weight; it there remains for a short time in unreliable balance, while the vibrator continuing its downward movement causes the chuck to enclose (i.e. receive) the head of the pile. Meanwhile, the binding cables or chains 8, are slackened but remain connected as safety links.

In phase V, liquid under pressure (i.e. hydraulic fluid) is forced from the hydraulic pump of the crane into the hydraulic chambers of the chuck; when the object is rigidly fixed to the vibrator, this is driven and the suspension cable of the crane continues to be slackened, while the pile subjected to the vibration is driven into the soil.

When, depending upon the elasto-plastic properties of the soil, it is necessary that the vibrator work as a rebounding rarn, the rigid connection between pile and chuck is loosened and is re-established if necessary during the working process by control of the hydraulic chambers.

When the object has been sufiiciently rammed in, so that the safety links formed by the cables or chains 8 are no longer needed and if these cables have reached a position, easily accessible from the ground, the cables are untied, so that after the end of pile driving a new working cycle may immediately begin.

For ramming of the objects at angles to the ground with corresponding manipulation of the crane, the object is brought, in the beginning phase of the ramming, in the respective inclined position, this inclination being maintained during the whole ramming process, as a result of the invariable direction of the exciting force exerted by the unidirectional vibrator, of the adequate balance of the fixing device and of the guiding, given by the ground in which the ramming has been begun.

For ramming-in or pulling-out of spiral piles the suspension equipment has to be of a turning type, to permit the'vibrator to turn during the screwing up of the vibrator in the soil; it is advantageous that the vibrator may be provided with a controlling device, permitting the exertion of the exciting force concurrently with an exciting torque having the direction of the exciting force. For the pulling work the working process goes on with the inverse sequence of that of the pile driving.

I claim:

1. A chuck for attaching a vibrator to a pile. or other elongated body, comprising:

a downwardly open housing defining a chamber adapted to receive an end of the body, said chamber having a wall provided with a window;

a clamping member receivable in said window and displaceable transversely of said wall for engagement with said body to retain same against an opposing surface of the chamber;

a spring plate mounted on said wall and extending generally parallel to said wall and said member while engaging same for biasing said member away from a body received in said chamber into said window;

means on said housing defiining a hydraulic compartment laterally outwardly of said member; and

a diaphragm between said compartment and said member, bearing upon said member for urging same, counter to the bias of said spring plate thereon, in the direction of a body received in said chamber upon pressurization of said compartment.

2. A chuck as defined in claim 1 wherein said housing is provided with counterweight opposite said compartment for maintaining the center of gravity of the chuck aligned with the axis of said chamber, said chamber being prismatic and said surface constituting a further wall opposite said first-mentioned wall.

3. A chuck as defined in claim 2, further comprising a pair of flexible members secured to said housing on opposite sides thereof and engageable with said body for linking said body to said housing independently of said memben References Cited UNITED STATES PATENTS 1,879,993 9/1932 Salmon 6153.5 3,101,956 8/1963 Muller 279-4 3,364,533 1/1968 Sibrava 24243 ROBERT C. RIORDON, Primary Examiner J. C. PETERS, Assistant Examiner U.S. Cl. X.R. 

